/*
 * Copyright 2002-2019 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.web.reactive.function.client;

import java.util.List;
import java.util.function.Consumer;

import org.springframework.http.codec.ClientCodecConfigurer;
import org.springframework.http.codec.HttpMessageReader;
import org.springframework.http.codec.HttpMessageWriter;

/**
 * Provides strategies for use in an {@link ExchangeFunction}.
 *
 * <p>To create an instance, see the static methods {@link #withDefaults()},
 * {@link #builder()}, and {@link #empty()}.
 *
 * @author Brian Clozel
 * @author Arjen Poutsma
 * @since 5.0
 */
public interface ExchangeStrategies {

    /**
     * Return an {@code ExchangeStrategies} instance with default configuration
     * provided by {@link ClientCodecConfigurer}.
     */
    static ExchangeStrategies withDefaults() {
        return DefaultExchangeStrategiesBuilder.DEFAULT_EXCHANGE_STRATEGIES;
    }

    /**
     * Return a builder pre-configured with default configuration to start.
     * This is the same as {@link #withDefaults()} but returns a mutable builder
     * for further customizations.
     */
    static Builder builder() {
        DefaultExchangeStrategiesBuilder builder = new DefaultExchangeStrategiesBuilder();
        builder.defaultConfiguration();
        return builder;
    }

    /**
     * Return a builder with empty configuration to start.
     */
    static Builder empty() {
        return new DefaultExchangeStrategiesBuilder();
    }


    // Static builder methods

    /**
     * Return {@link HttpMessageReader HttpMessageReaders} to read and decode the response body with.
     *
     * @return the message readers
     */
    List<HttpMessageReader<?>> messageReaders();

    /**
     * Return {@link HttpMessageWriter HttpMessageWriters} to write and encode the request body with.
     *
     * @return the message writers
     */
    List<HttpMessageWriter<?>> messageWriters();

    /**
     * Return a builder to create a new {@link ExchangeStrategies} instance
     * replicated from the current instance.
     *
     * @since 5.1.12
     */
    default Builder mutate() {
        throw new UnsupportedOperationException();
    }


    /**
     * A mutable builder for an {@link ExchangeStrategies}.
     */
    interface Builder {

        /**
         * Customize the list of client-side HTTP message readers and writers.
         *
         * @param consumer the consumer to customize the codecs
         * @return this builder
         */
        Builder codecs(Consumer<ClientCodecConfigurer> consumer);

        /**
         * Builds the {@link ExchangeStrategies}.
         *
         * @return the built strategies
         */
        ExchangeStrategies build();
    }

}
